Reading your results: our status codes and what they mean

The most crucial fields in the validation report for understanding your email verification results when you validate email addresses are Classification and Status. In the Classification field, there are four well-defined output values:

  • Deliverable, meaning the email is considered safe to send;
  • Risky, when the email is undesirable or sending to it may result in a bounce;
  • Undeliverable, when the email is known to be undeliverable and will likely generate a bounce;
  • Unknown, in the rare cases where we couldn't classify the email into any of the other groups.

On the other hand, the Status field can have various values, and we provide general recommendations for most customers for each value listed below.

How are classifications assigned?

Verifalia includes a default classification scheme that provides the Classification for each Status we support, offering optimal classifications for common situations. However, users have the flexibility to customize the classification scheme for their Verifalia account to meet more specialized needs. Furthermore, it is possible to set up classification overrides, which allow you to define wildcard expressions linked to particular classifications, that take effect before the system assesses the classification scheme.

When dealing with non-definitive or risky results, we strongly suggest considering your specific requirements: you can either reject all results not labeled as Success or accept some of them, depending on your flexibility.

Status codes

AtSignNotFound

Invalid email format: the @ symbol, used to separate the local part from the domain part of the address, has not been found.

CatchAllConnectionFailure

Failed to validate, a connection error occurred while verifying the catch-all settings on the external mail server. Retrying the validation may result in a definitive response.

CatchAllValidationTimeout

Validation failed due to a timeout while verifying the rejection of a fake email address by the mail server. Trying a higher results quality level is likely to provide a definitive response.

DnsConnectionFailure

A socket connection error occurred while querying the DNS servers for records about the domain. Trying a higher results quality level is likely to provide a definitive response.

DnsQueryTimeout

A timeout occurred while querying the DNS servers for records about the domain. Trying a higher results quality level is likely to provide a definitive response.

DomainDoesNotExist

Invalid email address, the domain does not exist.

DomainHasNullMx

Invalid email address, the domain has a null MX record: incoming emails to addresses at that domain will be bounced back to the sender as undeliverable, as there's no designated mail exchanger to handle them.

DomainIsMisconfigured

Invalid email address, the domain lacks valid DNS records and cannot receive messages from external hosts on the Internet..

DomainIsWellKnownDea

High-risk email type, the address is associated with a well-known disposable / throw-away email provider. A disposable email provider, often referred to as DEA provider, is a service that offers temporary and anonymous email addresses for short-term use.

DomainPartCompliancyFailure

Invalid email format: the domain part of the email address does not comply with IETF standards.

DoubleDotSequence

Invalid email format: an invalid sequence of two adjacent dots has been found. For example, john..smith@example.com

Duplicate

The email is a duplicate of another entry that has been previously verified in this list. We mark duplicated items (starting from the second email address onward) with the status Duplicate and leave them available for download in your completed email verification jobs; also, duplicated items do not deduct credits from your Verifalia balance.

InvalidAddressLength

Invalid email format: the email address has an invalid total length.

InvalidCharacterInSequence

Invalid email format: an invalid character has been detected in the provided sequence.

InvalidEmptyQuotedWord

Invalid email format: an invalid quoted word with no content has been found. Quoted words in email addresses refer to portions of the email address that are enclosed within double quotation marks ("): these quoted words are used to include special characters or spaces within an email address's local part (the part before the "@" symbol) that would otherwise not be allowed. For example, john."".smith@example.com

InvalidFoldingWhiteSpaceSequence

Invalid email format: an invalid folding white space (FWS) sequence has been found. Folding white space (FWS) is a concept defined in the Internet email standards (RFC 5322) and refers to the use of white space (spaces, tabs, or line breaks) to format and structure certain parts of an email header, including the message body. For example, john \rsmith@example.com (where \r is the line feed symbol).

InvalidLocalPartLength

Invalid email format: the local part of the email address has an invalid length.

InvalidWordBoundaryStart

Invalid email format: a new word boundary has been detected at an invalid position.

IspSpecificSyntaxFailure

Following the syntactic rules of the target mail exchangers for the domain, the address is considered syntactically invalid.

LocalEndPointRejected

Validation failed because the external mail exchanger rejected the local endpoint. Trying a higher results quality level is likely to provide a definitive response.

LocalSenderAddressRejected

Validation failed because the external mail exchanger rejected the local sender address. Trying a higher results quality level is likely to provide a definitive response.

MailboxConnectionFailure

Failed to validate, a connection error occurred while validating the mailbox for the email address. Retrying the validation may result in a definitive response.

MailboxDoesNotExist

The mailbox for the email address does not exist.

MailboxHasInsufficientStorage

The mailbox for the email address is either over its storage quota, or the mail exchanger has insufficient system storage.

MailboxIsDea

High-risk email type, the address is associated with a well-known disposable / throw-away email provider. A disposable email provider, often referred to as DEA provider, is a service that offers temporary and anonymous email addresses for short-term use.

MailboxTemporarilyUnavailable

Validation failed because the requested mailbox is temporarily unavailable. This doesn't necessarily mean the mailbox doesn't exist; it's often a response from mail exchangers with greylisting enabled. Trying a higher results quality level is likely to provide a definitive response.

MailboxValidationTimeout

Validation failed due to a timeout while verifying the existence of the mailbox. Trying a higher results quality level is likely to provide a definitive response.

MailExchangerIsHoneypot

High-risk email type: the email address is a honeypot (also known as spamtrap). We strongly advise removing honeypots from your lists.

MailExchangerIsWellKnownDea

High-risk email type, the address is associated with a well-known disposable / throw-away email provider. A disposable email provider, often referred to as DEA provider, is a service that offers temporary and anonymous email addresses for short-term use.

ServerDoesNotSupportInternationalMailboxes

Invalid email address: the external mail exchanger does not support international mailbox names. To support this feature, mail exchangers must comply with RFC 5336 and announce support for both the 8BITMIME and UTF8SMTP protocol extensions.

ServerIsCatchAll

Possibly risky email type: the external mail exchanger accepts fake and nonexistent email addresses. Therefore, the provided email address may not exist, and the existence of the individual mailbox cannot be verified.

ServerTemporaryUnavailable

Validation failed because the requested mail exchanger is temporarily unavailable, possibly due to system maintenance or other transient conditions. This doesn't necessarily mean the email address isn't valid; trying a higher results quality level is likely to provide a definitive response.

SmtpConnectionFailure

A socket connection error occurred while trying to connect to the mail exchanger that serves the email address domain. Trying a higher results quality level is likely to provide a definitive response: if the issue persists, it indicates that the domain associated with the email address is unable to accept email messages.

SmtpConnectionTimeout

A timeout occurred while trying to connect to the mail exchanger that serves the email address domain. Trying a higher results quality level is likely to provide a definitive response: if the issue persists, it indicates that the domain associated with the email address is unable to accept email messages.

SmtpDialogError

Validation failed because the external mail exchanger replied in a non-standard way. Trying a higher results quality level is likely to provide a definitive response.

Success

Valid email, with no high-risk factors detected: safe to send mail.

UnbalancedCommentParenthesis

Invalid email format: the number of parentheses used to open comments is not equal to the number used to close them. Comments in email addresses are a way to include additional information or annotations within an email address without affecting the functionality of the address. For example, john.)smith@example.com

UnexpectedQuotedPairSequence

Invalid email format: an unexpected quoted pair sequence has been found within a quoted word. Quoted words in email addresses refer to portions of the email address that are enclosed within double quotation marks ("): these quoted words are used to include special characters or spaces within an email address's local part (the part before the "@" symbol) that would otherwise not be allowed.

UnhandledException

Validation failed due to unexpected technical issues during the processing of this email address. Retry may provide a definitive response.

UnmatchedQuotedPair

Invalid email format: a quoted pair within a quoted word is not properly closed. Quoted words in email addresses refer to portions of the email address that are enclosed within double quotation marks ("): these quoted words are used to include special characters or spaces within an email address's local part (the part before the "@" symbol) that would otherwise not be allowed.

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